Method of partially forming oxide layer

ABSTRACT

The present invention provides a method of partially forming oxide layers on a surface of a substrate such as a glass plate by forming an oxide layer on the surface of the substrate, partially contacting the surface of the oxide layer formed on the substrate with an inorganic compound different from the oxide, dissolving partially the layer with the inorganic compound and removing the dissolved components of the layer together with the inorganic compound, by which the oxide layers are partially formed on the surface of the substrate efficiently and surely.

TECHNICAL FIELD

The present invention belongs to a technical field of an inorganicsubstrate having formed thereon oxide layer, which is used forautomobiles, buildings, various industrial instruments, etc.Particularly, the invention belongs to a technical field of an inorganicsubstrate having formed oxide layer on the necessary portions only ofthe surface thereof.

BACKGROUND ART

On the surface of a glass plate or a ceramic plate, oxide layers havingvarious functions according to the use are formed. For example, asglasses used for automobiles, vehicles, buildings, etc., aheat-reflective layer containing the oxide of titanium, cobalt, etc., isgenerally used for the purpose of reducing the cooling load, etc. Also,as glass substrates for various displays, an electrically conductivefilm comprising tin oxide, etc., is used from the necessity of elementdriving. These layers are frequently formed on only parts of the surfaceof a substrate for the necessity of each use described above.

In not only the use of display but also other uses of automobiles,buildings, etc., there is a case of requiring that the layer ispartially formed. For example, in the case of using a heat-reflectiveglass for the back window of automobile, it is required that a layer isnot formed on the glass surface adjacent to a high-mount stop lampdisposed in the inside of the back window of the automobile but a layeris formed on other portion of the glass surface for shielding heat rayswhile ensuring visibility of the lamp.

In such a case, a method of foaming the layer after previously applyingmasking to the necessary portion of the glass plate or a method ofapplying masking after forming a layer on the whole glass plate andremoving the remaining unmasked portion of layer with a solvent, byreleasing, or polishing, etc., is employed.

However, according to the conventional methods as described above,masking is required in any method, which is accompanied by complicatedsteps and operations, and thus the effective and ensure partialformation of layer has been difficult by the conventional methods.

DISCLOSURE OF THE INVENTION

The present invention has been made for solving the above-describedproblems and an object of the present invention is to provide a methodof partially forming a layer on the surface of a substrate by a simpleand ensure method.

According to the present invention, the above-described object can beattained by the method of partially forming an oxide layer on thesurface of an inorganic substrate, comprising

a step of forming a layer comprising an oxide on the surface of theinorganic substrate,

a step of contacting the layer of a definite range to be removed withother inorganic compound than the above-described oxide to dissolve theabove-described layer of the definite range with the inorganic compound,and

a step of removing the dissolved layer of the above-described definiterange together with the above-described inorganic compound.

Also, the preferred embodiments of the present invention are as follows.

(1) The melting point of the above-described inorganic compound is 500°C. or lower or the softening point thereof is 500° C. or lower.

(2) The above-described dissolving step is a step of carrying out thedissolution by heating the oxide layer of the definite range togetherwith the above-described inorganic compound.

(3) The above-described inorganic compound includes at least one kindselected from the group consisting of phosphorus compounds eachcontaining oxygen as a constituent and boron compounds each containingoxygen as a constituent.

(4) The above-described phosphorus compound includes at least one kindselected from the group consisting of phosphoric acid and phosphates andthe above-described boron compound includes boric acid and borates.

(5) The above-described inorganic compound is a glass and contains atleast one kind selected from the group consisting of P₂O₅, PbO, B₂O₃,ZnO, and Bi₂O₃ as the constituent.

The inorganic compound used in the present invention may be an inorganiccompound which can dissolve the oxide of the layer when the compound iscontacted with the oxide constituting the layer and further thecontacted layer is heated and can keep the structure and the physicalcharacteristics of the inorganic substrate, and can be properly selectedaccording to the properties of the layer and the substrate. As a methodof removing the above-described inorganic compound after dissolving thelayer, a physical means and/or a chemical means can be applied. Forexample, as the physical means, there are wiping off, blowing off, etc.,and as the chemical means, there are dissolving of the layer with asolvent, etc. As a preferred embodiment of a preferred removing means ofa layer, there is cleaning with an organic solvent such as alcohols(e.g., methanol and ethanol) followed by drying and as the case may be,the means can be carried out together with the above-described physicalmeans.

In the present invention, it is preferred that about the layer to beremoved, which corresponds to the region of existing the inorganiccompound contacted with the layer, all the layer of the correspondingregion is removed, but the residue of the layer to an extent of notpreventing the visibility can be allowed in this invention.

As the inorganic compounds which are generally used in this invention,there are phosphorus compounds containing oxygen as the constituent,boron compounds containing oxygen as the constituent, etc., each havinga melting point of 500° C. or lower and being a liquid at normaltemperature. Preferably, there are phosphoric acids, phosphates, boricacid, and borates satisfying the above-described conditions as shownbelow. The phosphoric acid in this invention means the general names ofthe acids formed by the hydration of diphosphorus pentoxide and includesorthophosphoric acid (H₃PO₄, liquid at normal temperature),pyrophosphoric acid (H₄P₂O₇, liquid at normal temperature),triphosphoric acid (H₅P₃O₁₀, liquid at normal temperature), etc. Also,practical examples of the phosphate include sodium dihydrogenphosphate(NaH₂PO₄) (typically, dihydrate: NaH₂PO₄.2H₂O, melting point 60° C.) andpotassium dihydrogenphosphate (KH₂PO₄, melting point 96° C.). Theborates practically include boric acid (H₃BO₃, melting point 185° C.),etc.

Furthermore, as the inorganic compound having a melting point of 500° C.or lower, there are glasses. As the glass, glasses having generally alow-melting point composition (so-called low-melting glasses) aresuitable and the glasses containing P₂O₅, B₂O₃, ZnO, PbO, Bi₂O₃, etc.,are preferred. Practically, the glass composition series such as anR₂O—P₂O₅ series, an R₂O—B₂O₃ series, a PbO—B₂O₃—ZnO series, aPbO—SiO₂—B₂O₃ series, a Bi₂O₃—ZnO—B₂O₃ series, an R₂O—ZnO—SiO₂—B₂O₃series, a ZnO—B₂O₃ series, an R₂O—ZnO—P₂O₅ series (wherein, R representsan alkali metal such as Na, K, etc.), etc., can be suitably used.

In the present invention, it is a feature that by contacting theinorganic compound with the oxide constituting the layer, the layer isdissolved. To practice the dissolution of the layer, it is morepreferred that the inorganic compound is contacted with only a portionof the surface of the layer and dissolution of the layer is progressed.

Furthermore, it is preferred to dissolve the layer by heating in thestate that the inorganic compound is contacted with the oxideconstituting the layer. To practice the dissolution of the layer, it ismore preferred to contact the inorganic compound with only a part of thesurface of the layer and progress the dissolution of the layer byheating.

As a method of selectively contacting the inorganic compound with a partof the layer, the following method can be illustrated.

(1) A liquid, powders, or granules each containing the inorganiccompound are placed on a part of the surface of the layer.

(2) A paste obtained by mixing the inorganic compound with an organicsolvent, a solid powder, etc., is coated on a part of the surface of thelayer.

(3) A liquid formed by dissolving or dispersing the inorganic compoundin a solvent is coated on a part of the surface of the layer and, ifnecessary, the coated surface is dried.

(4) A substance attached or impregnated with the inorganic compound isplaced on a part of the surface of the layer.

After contacting the inorganic compound with a part of the surface ofthe layer by the method typified by these methods (1) to (4), thesubstrate is generally heated (as the case may be, the circumferenceonly of the inorganic compound thus applied is heated). When theinorganic compound is originally a solid, the compound is melted by aheating step. Before melting the inorganic compound, the powders, thegranules, the paste, etc., is usually fluidized and attached to thesurface of the layer.

There is no particular limitation on the organic solvent in the method(2) but a water-soluble organic solvent is preferred. As thewater-soluble, a mixture of one kind of water-soluble resins such as amodified ethyl cellulose resin, a modified polyamide resin, and polymerssuch as n-vinylpyrrolidone, etc.) and one kind of water-soluble solventssuch as oxyethylene glycol ether, propylene glycol, and propylene glycolether) is preferably used. The mixing ratio of the mixture is properlycontrolled according to the kinds and the amounts of the inorganiccompound, the solid powder, etc.

When the inorganic compound is a liquid substance, the compound can beselectively contacted with the desired portion(s) of the surface of thelayer without need of a heating step. Also, when the inorganic compoundis a liquid substance, the substance itself previously heated and candissolve the desired portions of the layer by a method of directlyblowing onto the portions, dropping onto the portions, etc. In thiscase, it is preferred to heat the substrate to the same temperature asthe temperature of heating the substance, particularly in the case of aglass substrate, from the point of preventing the substrate from beingbroken by heating.

Considering the heat efficiency in the heating step as described above,when the inorganic compound is a solid, the melting point thereof isgenerally preferably low and for example, when the substrate is a glassplate, it is required that the melting point of the inorganic compoundis lower (when a soda-lime glass is used as the substrate, 735° C. orlower) than at least the softening point (the temperature at which theviscosity is 4.5×10⁷ poise) of the glass. In addition, when a glass isused as the inorganic compound, it is required that the softening pointof the glass is lower than the softening point of the glass constitutingthe substrate. The softening point of the inorganic compound or thesoftening point of a glass is preferably 500° C. or lower, morepreferably 350° C. or lower, and most preferably 200° C. or lower, fromthe points of energy saving and the ease of handling.

There is no particular limitation on the inorganic substrate used inthis invention but a glass plate is suitable. Also, there is noparticular limitation on the glass plate and the plates of aborosilicate glass, an aluminosilicate glass, and various kinds ofcrystallized glasses can be used but typically the plate of a sodasilicate glass (soda-lime silica glass) is used. Also, the substratemade up of a ceramic such as alumina may be used.

As the oxide layer used in this invention, a film which functions as aheat-reflecting film, a heat-absorbing film, a colored film, anelectrically conductive film, etc., can be used. Furthermore, the oxidelayer may contain, in addition to the oxide, a nitride, a carbide, ametal, etc., in the range of not reducing the above-described objects ofthis invention.

For example, the heat-reflective film includes a film comprising theoxide of at least one element of cobalt, nickel, chromium, iron,titanium, tin, and antimony. More practically, there are a filmcomprising titanium oxide as the main constituent, a film comprising theoxide of a metal including cobalt as the main constituent, a filmcomprising the oxides of tin and antimony as the main constituents, etc.The heat-reflective film may further properly contain silicon, aluminum,zinc, copper, indium, bismuth, vanadium, manganese, zirconium, etc., inaddition of the above-described element for reducing the reflectance andfinely controlling the color tone.

Also, the electrically conductive film includes a film comprising tinoxide added with slide components) (one or two or more kinds ofchlorine, fluorine, antimony, etc.), a film essentially comprisingindium oxide or comprising indium oxide containing tin, a filmcomprising zinc oxide added with a slight amount of other component(e.g., aluminum), etc.

As a method of forming a layer from an oxide, a sputtering method, avacuum vapor deposition method, a liquid-phase film-forming method,etc., as well as a so-called thermal decomposition method, that is, amethod of forming an oxide film on the surface of a substrate bythermally decomposing a raw material compound on the surface of ahigh-temperature glass plate and oxidizing can be used. As the thermallydecomposing method, a method of coating a metal compound on the surfaceof a substrate followed by burning, a method of sending the vapor of ametal compound onto a substrate heated to a high temperature (CVDmethod), a method of blowing a solution or a dispersion obtained bydissolving or dispersing a metal compound in an organic solvent as fineliquid droplets (splaying method), etc., can be used.

In addition, as the step of forming the oxide layer, a step of forming alayer on the surface of a glass ribbon in a floating production methodis preferred. A method of continuously forming an oxide layer on thesurface of a glass ribbon by a thermal decomposition method in afloating production method is a preferred film-forming method in theproduction efficiency because the remaining heat of the glass melt canbe utilized for the formation of the layer but a simple method ofpatterning by partially removing a layer has not yet been found. Thepresent invention can be particularly suitably practiced for suchfilm-forming.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(a)-FIG. 1(d) are schematic views showing an embodiment of thepresent invention from the direction of the cross-section of asubstrate.

FIG. 2(a)-FIG. 2(d) are schematic views showing other embodiment of thepresent invention from the direction of the cross-section of asubstrate.

FIG. 3 is a schematic view showing an embodiment in the case of applyingthe present invention to a back window of an automobile.

The numerals are as follows.

1: Inorganic substrate,

2 and 12: Oxide layer,

3: Inorganic compound powder,

13: Paste containing an inorganic compound,

4 and 14: Dissolved layer portion,

5: Layer-removed portion, and

15: Back window for automobile.

An embodiment of the practice of the present invention is explained byFIG. 1. On the surface of an inorganic substrate 1 is formed an oxidelayer 2 (FIG. 1(a)) and powders 3 of an inorganic compound are placed ondefinite ranges of the layer 2 (FIG. 1(b)). The substrate having formedthereon the layer is then heated to fluidize the powders 3, whereby theinorganic compound is contacted with the surface of the layer in amolten state. The inorganic compound dissolves the layer and saidportions become the states that the dissolved components of the layerintermix in the inorganic compound (FIG. 1(c)). When the substrate isimmersed in a liquid or is washed with a liquid, the inorganic compoundhaving intermixed therein the dissolved components of the layer isdissolved in the liquid. Thereby, the layer of the portions is removed,and as a result, the layers are partially formed on the surface of thesubstrate 1.

Other embodiment of the present invention is explained by FIG. 2. On thesurface of a glass plate 11 is formed an oxide layer 12 (FIG. 2(a)) anda pasty compound 13 obtained by adding an organic solvent to aninorganic compound is placed on definite portions of the surface of thelayer 12 (FIG. 2(b)). The glass plate 11 is then heated to fluidize thepaste 13 and the inorganic compound contained therein is contacted tothe surface of the layer in a molten state. The inorganic compounddissolves the layer, whereby said portions become the state that thedissolved components of the layer are intermixed in the inorganiccompound (FIG. 2 (c)). Together with the heating step described above, abending work is applied to the heated glass plate 11 to make a definiteform. Furthermore, the heated glass plate 11 is quenched to cause acompression stress on the surface to provide a so-called tempered glass.Finally, when the substrate is immersed in a liquid or washed with aliquid, the inorganic compound having intermixed therein the dissolvedcomponents of the layer is dissolved in the liquid. Thereby, the layerof the portions is removed and as a result, the layers are partiallyformed on the surface of the molded and tempered glass 11.

In addition, in the above-described embodiments, the case that theinorganic compound was solid at normal temperature was described butwhen the inorganic compound is a liquid substance at normal temperature,such as phosphoric acid, etc., the embodiment of this case is also thesame as above except the point that the inorganic compound is in aliquid state before the heating step.

When a glass plate is used as the inorganic substrate as in theembodiment of the present invention shown in FIG. 2, by utilizing theheating step at dissolving the inorganic compound and the layer,tempering and/or a bending work of the glass plate can be practiced.When melting of the layer and the secondary work of a glass plate asdescribed above are practiced by the same heating step, the productionmethod is very advantageous in the production efficiency. In addition,the tempered and bending worked glass plate described above is useful asa glass for automobile and, in particular, when only the portion of thelayer necessary for the visibility of a high-mount stop lamp is removed,the glass becomes useful as a glass for a back window of automobile(see, FIG. 3). As the oxide layer in this case, a heat-reflective filmcan be illustrated.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is described in detail below by the followingexamples.

EXAMPLE 1

A substantially green soda-lime silica glass (visible lighttransmittance 81% by light source A, and hereinafter the same) having asize of 150 mm×150 mm and a thickness of 3.4 mm was washed and dried toprovide a substrate. The substrate was fixed by a hanging means andmaintained for 5 minutes in an electric furnace set at 650° C.Thereafter, the glass plate was taken out and a raw material liquiddescribed below was sprayed onto the substrate using a commerciallyavailable spray gun under the conditions of an air pressure of 3.0kg/cm², an air amount of 90 liter/minute, and a straying amount of 20ml/minute.

As a result, an oxide layer composed of cobalt, chromium, and iron wasformed as a heat-reflective film. The result of obtaining the weightpercentages of cobalt, iron, and chromium occupying the total metalweights per unit area of the heat-reflective film by a high-frequencyplasma emission spectrochemical analysis showed that cobalt was 84%,chromium 10%, and iron 6%. In addition, the above-described raw materialliquid was prepared by dissolving 12.5 g of dipropionylmethane oftrivalent cobalt, 0.62 g of acetyl acetonate of trivalent iron, and 1.83g of acetyl acetonate of chromium in 100 ml of toluene.

Then, a 1:1 (by weight ratio) mixture of sodium dihydrogenphosphate(NaH₂PO₄.2H₂O, melting point 60° C.) and ethanol was coated on an areaof a part (50 mm×50 mm) of the surface of the layer thus formed at athickness of about 10 μm. Thereafter, the substrate was maintained in anelectric furnace maintained at a temperature of 200° C. for 3 minutes toevaporate off organic materials and further the heat-reflective glasswas maintained in the same electric furnace at a temperature of 650° C.for 5 minutes. When after cooling, the substrate was washed to removethe coated material, the visual check revealed that the layer at theportion had been removed and the surface of glass was partially exposed.

When about the layer-removed portion and the layer-remaining portion,each visible light transmittance was measured to determined whether ornot the above-described layer was completely removed, the visible lighttransmittance of the layer-removed portion was 81%, which was the sameas that of the soda-line silica glass of the substrate before formingthe layer, while the visible light transmittance of the layer-remainingportion was 31%. From the result, it was confirmed that theabove-described layer had been completely removed.

Also, even when a tempering treatment of the glass plate was carried outby blowing a compressed air onto the glass plate after theabove-described heat-treatment step of 650° C., the same result as abovewas obtained. Furthermore, when a tempering treatment of the glass platewas carried out by applying a bending work to the glass plate whilequenching by blowing a compressed air onto the glass plate after theabove-described heat treatment of 650° C., the same result as above wasobtained.

In addition, when the sodium ion concentration on the surface of theglass plate obtained in the example was measured by a secondary ion massspectrographic method (SIMS), it was found that the ion concentrationdiffers between the layer-removed portion and the layer-remainingportion.

EXAMPLE 2

When the formation of layer and the treatment were practiced byfollowing the same procedure as Example 1 except that potassiumdihydrogenphosphate (KH₂PO₄, melting point 96° C.) was used as aninorganic compound in place of sodium dihydrogenphosphate, aheat-reflective film could be partially formed as in Example 1. Thevisible light transmittance was 81% at the layer-removed portion and 31%at the layer-remaining portion.

EXAMPLE 3

By following the same procedure as Example 1 except that boric acid(H₃BO₃, melting point 185° C.) was used as an inorganic compound inplace of sodium dihydrogenphosphate, a heat-reflective film waspartially formed. The visible light transmittance was 81% at thelayer-removed portion and 31% at the layer-remaining portion.

EXAMPLE 4

To a solution obtained by dissolving 100 g of sodium dihydrogenphosphate(NaH₂PO₄.2H₂O, melting point 60° C.) in 200 g of water was added 100 gof ethanol. While sufficiently stirring the liquid, the liquid was blownonto a definite range of the heat-reflective layer as same as in Example1 using a spray gun. Thereafter, patterning was practiced as inExample 1. The visible light transmittance was 81% at the layer-removedportion and 31% at the layer-remaining portion.

EXAMPLE 5

By following the same procedure as Example 1 except that a low-meltingglass powder (softening point about 300° C.) having a glass compositionof 81% of PbO, 4% of ZnO, and 15% of B₂O₃ by weight ratio was used as aninorganic compound in place of sodium dihydrogenphosphate, aheat-reflective film was partially formed. The coated substrate waswashed with warm water of 85° C. The visible light transmittance was 81%at the layer-removed portion and 31% at the layer-remaining portion.

EXAMPLE 6

A paste was prepared by mixing orthophosphoric acid (H₃PO₄, liquid atnormal temperature), water-soluble organic solvents (a mixture ofpolyamide, a cellulose, and propylene glycol), and a carbon powder at1:1:0.6 by weight ratio. The paste was coated on a part of the layer assame as in Example 1 at a thickness of about 10 μm. Thereafter, thecoated substrate was heat-treated by maintaining for 5 minutes in anelectric furnace maintained at a temperature of 200° C. When aftercooling, the coated paste was removed by washing, the layer at thepaste-coated portion had been completely removed and thus aheat-reflective film could be partially formed. The glass was subjectedto a tempering treatment by heating to 650° C. in a bend-temperingfurnace to apply a bending work and quenching by blowing compressed aironto the glass as in Example 1. The visible light transmittance was 81%at the layer-removed portion and 31% at the layer-remaining portion.

EXAMPLE 7

A colorless soda-lime silica glass (visible light transmittance 88%)having a size of 150 mm×150 mm and a thickness of 6 mm was used as asubstrate, and the raw material liquid described below was blown ontothe substrate as in Example 1 for about 5 seconds under the conditionsof an air pressure of 1.5 kg/cm², an air amount of 50 liters/minute, anda spraying amount of 100 ml/minute. As a result, an oxide layer composedof cobalt, nickel, and iron was formed as a heat-reflective film. Theresult of obtaining the weight percentages of cobalt, nickel, and ironoccupying the total metal weights per unit area of the heat-reflectivefilm by a high-frequency plasma emission spectrochemical analysis showedthat cobalt was 70%, nickel 21%, and iron 9%. The above-described rawmaterial liquid was prepared by dissolving 2.7 g of acetyl acetonate oftrivalent cobalt, 0.6 g of dipropionyl methane of divalent nickel, and0.3 g of acetyl acetonate of trivalent iron in 100 ml of toluene.

Thereafter, by practicing patterning of the layer and bend-tempering ofthe glass as in Example 6, a heat-reflective film was partially formed.The visible light transmittance was 88% at the layer-removed portion and37% at the layer-remaining portion.

EXAMPLE 8

A paste was prepared by mixing pyrophosphoric acid (H₄P₂O₇, liquid atnormal temperature), the water-soluble organic solvents as used inExample 6, and a carbon powder at 1:1:0.65 by weight ratio. Using thepaste, as the case of the layer in Example 7, a heat-reflective film waspartially formed. The visible light transmittance was 88% about thelayer-removed portion and 37% about the layer-remaining portion.

EXAMPLE 9

A colorless soda-lime silica glass (visible light transmittance 88%)having a size of 150 mm×150 mm and a thickness of 6 mm was used as asubstrate and a raw material solution prepared by mixing dibutyltinfatty acid [(C₄H₉)₂Sn(OCOC₇H₁₅)₂], toluene, xylene, isopropyl alcohol,and triphenyl antimony was blown onto the substrate by a spray gun. As aresult, an oxide film composed of tin and antimony was formed as aheat-reflective film.

Then, pyrophosphoric acid was attached to all over the surface of 30mm×30 mm of charcoal cut into the size of 30 mm×30 mm×10 mm. Thecharcoal was calmly placed on the surface of the layer such that theliquid-attached surface was in contact with the layer and they wereheat-treated by maintaining for 5 minutes in an electric furnacemaintained at a temperature of 200° C. When after cooling, the charcoalwas removed and the liquid components were removed by washing, the layerat the liquid-contact portion had been completely removed and aheat-reflective film composed of the oxides of tin and antimony as themain constituents could be partially formed. The visible lighttransmittance was 88% at the layer-removed portion and 69% at thelayer-remaining portion.

EXAMPLE 10

A colorless soda-lime silica glass (visible light transmittance 88%)having a size of 150 mm×150 mm and a thickness of 6 mm was used as asubstrate, a raw material solution formed by mixing titaniumdi-normalpropoxybisacetyl acetonate, toluene, and xylene was blown ontothe substrate as in Example 1 by a commercially available spray gun. Asa result, an oxide film composed of titanium was formed as aheat-reflective film.

Then, a sponge made of carbon fibers was impregnated with pyrophosphoricacid was calmly placed on the layer and while contacting pyrophosphoricacid impregnated in the sponge with the layer, the substrate washeat-treated by maintaining for 5 minutes in an electric furnacemaintained at a temperature of 200° C. When after cooling, the carbonfiber-made sponge was removed and liquid components were removed bywashing, the layer at the sponge liquid-contacted portion had beencompletely removed and the heat-reflective film composed of titaniumoxide as the main constituent could be partially formed. The visiblelight transmittance was 88% at the layer-removed portion and 62% at thelayer-remaining portion.

EXAMPLE 11

To 1 mol of titanium isopropoxide with stirring was added dropwise 2mols of acetyl acetone by a dropping funnel to provide a titanium oxideraw solution. Also, to 50 g of ethyl silicate were added 6 g of 0.1 Nhydrochloric acid and 44 g of ethyl cellosolve followed by stirring for2 hours at room temperature to provide a silicon oxide raw solution.Furthermore, to 10 g of cerium nitrate hexahydrate was added 7.16 g ofethyl cellosolve and the mixture was stirred for one hour at atemperature of 90° C. to provide a cerium oxide raw liquid containing23.2% CeO₂ solid component. Still further, by adding 9.00 g of ethylcellosolve to 1 g of chloroauric acid tetra-hydrate, a gold fineparticle raw liquid was prepared. Also, by adding 18.8 g of ethylcellosolve to 10 g of iron nitrate nonahydrate, an iron oxide rawsolution was obtained.

To a mixture of 0.433 g of the iron oxide raw solution, 1.31 g of thetitanium oxide raw solution, 1.41 g of the cerium oxide raw liquid, and0.815 g of silicon oxide raw solution described above was added 8.03 gof ethyl cellosolve and finally 3.00 g of the gold fine particle rawliquid was added followed by mixing with stirring to prepare a coatingliquid.

A substantially green soda-line silica glass (visible lighttransmittance 74%) having a thickness of 3.4 mm was used as a substrateand the above-described coating liquid was coated on the substrate byspin coating at a rotation number of 1000 rpm for 15 seconds. After airdrying, the substrate was heat-treated at 250° C. for 2 hours to depositthe gold fine particles. Then, burning was carried out at 720° C. for105 seconds to form a colored film of 210 nm in thickness on the glassplate.

A paste obtained by mixing orthophosphoric acid, the water-solubleorganic solvents, and a carbon powder as in Example 6 was coated on thecolored film, the glass plate was heat-treated by maintaining for 5minutes in a furnace maintained at a temperature of 250° C., and whenafter cooling, the coated film was washed, the colored film at thepaste-coated portion had been completely removed and the colored filmwas partially formed. The visible light transmittance was 74% at thelayer-removed portion and 27% at the layer-remaining portion.

EXAMPLE 12

A raw material liquid was prepared as in Example 11, coated on a glassplate by a spin coating method, and after air drying, the glass platewas heat-treated at 250° C. for 2 hours, whereby a colored film of 310nm in thickness having deposited thereon gold particles was formed onthe glass plate.

A paste obtained by mixing orthophosphoric acid, the water-solubleorganic solvents, and a carbon powder as in Example 6 was coated on thecolored film, the glass plate was heat-treated by maintaining for 5minutes in a furnace maintained at a temperature of 150° C., and whenafter cooling, the coated film was washed, the colored film at thepaste-coated portion had been completely removed. By applying thebend-tempering treatment as in Example 1 to the glass plate, a temperedbent glass plate having partially formed thereon colored films wasobtained. The thickness of the colored film after the bend-temperingtreatment was 210 nm. The visible light transmittance was 74% at thelayer-removed portion and 27% at the layer-remaining portion.

In addition, the composition of the colored films obtained in Examples11 and 12 was 16.1% of Au, 18.2% of SiO₂, 24.2% of TiO₂, 36.6% of CeO₂,and 4.9% of Fe₂O₃ by weight percentage.

EXAMPLE 13

A substantially green soda-lime silica glass (visible lighttransmittance 81%) having a thickness of 3.4 mm was used as a substrateand the raw material liquid described below was blown onto the substrateas in Example 1 for 5 seconds under the conditions of an air pressure of1.5 kg/cm², an air amount of 50 liters/minute, and a spraying amount of100 ml/minute. As a result, an oxide film composed of cobalt, iron,chromium, and nickel was formed as a heat-selective film. The result ofobtaining the weight percentages of cobalt, iron, chromium, and nickel,occupying the total metal weights per unit area of the heat-reflectivefilm by a high-frequency plasma emission spectrochemical analysis showedthat cobalt was 59.0%, iron 18,5%, chromium 22.0%, and nickel 0.5%. Theabove-described raw material liquid was prepared by dissolving 7.44 g ofacetyl acetonate of trivalent cobalt, 0.52 g of dipropionylmethane ofdivalent nickel, 1.87 g of acetyl acetonate of trivalent iron, and 1.83g of acetyl acetonate of chromium in 300 ml of toluene.

Then, while maintaining the glass substrate to 150° C., orthophosphoricacid heated to 150° C. was partially blown onto the substrate byspraying. When after cooling, the attached liquid was removed bywashing, the layer at only the liquid-blown portion had been removed andthe heat-reflective film could be partially formed. Thereafter, theglass plate was subjected to bend-tempering. The visible lighttransmittance was 81% at the layer-removed portion and 36% at thelayer-remaining portion.

EXAMPLE 14

A substantially green soda-lime silica glass (visible lighttransmittance 81%) having a thickness of 3.4 mm was used as a substrateand the raw material liquid described below was blown onto the substrateas in Example 13 for 5 seconds under the conditions of an air pressureof 1.5 kg/cm², an air amount of 50 liters/minute, and a spraying amountof 100 ml/minute. As a result, an oxide film composed of cobalt andnickel was formed as a heat-selective film. The result of obtaining theweight percentages of cobalt and nickel occupying the total metalweights per unit area of the heat-reflective film by a high-frequencyplasma emission spectrochemical analysis showed that cobalt was 73.8%and nickel 26.2%. The above-described raw material liquid was preparedby dissolving 7.12 g of acetyl acetonate of trivalent cobalt and 3.13 gof dipropionylmethane of divalent nickel in 300 ml of toluene.

Then, while heating the glass substrate to 150° C., orthophosphoric acidheated to 150° C. was partially added dropwise to the surface of thelayer. When after cooling, the attached liquid was removed by washing,the layer at only the liquid-dropped portion had been removed and theheat-reflective film could be partially formed. Thereafter, the glassplate was subjected to bend-tempering. The visible light transmittancewas 81% at the layer-removed portion and 34% at the layer-remainingportion.

EXAMPLE 15

Orthophosphoric acid was partially coated on the surface of the layer assame as in Example 1 at a thickness of about 1 mm and the substrate wasallowed to stand for 24 hours at normal temperature (25° C.). Whenthereafter, the attached liquid was removed by washing, the layer at thecoated portion with orthophosphoric acid had been completely removed anda heat-reflective film could be partially formed. The glass plate washeated to 650° C. in a bend-tempering furnace and subjected to atempering treatment by applying bending work and quenching by blowing acompressed air thereto. The visible light transmittance was 81% at thelayer-removed portion and 31% at the layer-remaining portion regardlessof the application or non-application of bend-tempering.

INDUSTRIAL APPLICABILITY

According to the present invention, after forming an oxide layer on aninorganic substrate, a partial formation of a layer can be efficientlyand surely practiced without need of masking accompanied by acomplicated step and a troublesome operation. By such a partialformation of the layer, functions such as an electrically conductiveproperty, a heat-reflective property, etc., can be simply imparted tothe surface of an optional substrate.

What is claimed is:
 1. A method of partially forming oxide layers on asurface of an inorganic substrate, consisting essentially of: (a) a stepof forming a layer comprising an oxide on the surface of an inorganicsubstrate; (b) a step of contacting a fixed portion of the oxide layerof step (a) with a paste comprising an inorganic compound, organicsolvents, and carbon powder in order to dissolve the oxide layer of step(a) with the paste, wherein said inorganic compound is not the same asthe oxide of step (a); and (c) a step of removing the dissolved portionof the oxide layer from step (b) together with the paste, wherein saidinorganic substrate is a glass plate.
 2. A method of partially formingoxide layers as claimed in claim 1, wherein said inorganic compound isphosphoric acid.
 3. A method of partially forming oxide layers on asurface of an inorganic substrate, consisting essentially of: (a) a stepof forming a layer comprising an oxide on the surface of an inorganicsubstrate; (b) a step of contacting a fixed portion of the oxide layerof step (a) with an inorganic compound in order to dissolve the oxidelayer of step (a) with the inorganic compound, wherein said inorganiccompound is not the same as the oxide of step (a); and (c) a step ofremoving the dissolved portion of the oxide layer from step (b) togetherwith the inorganic compound, wherein said inorganic substrate is a glassplate and said inorganic compound is a glass containing at least onecompound selected from the group consisting of P₂O₅, PbO, B₂O₃, ZnO, andBi₂O₃.
 4. A method of partially forming oxide layers as claimed in claim3, wherein the inorganic compound has a melting point of 500° C. orlower, or a softening point of 500° C. or lower.
 5. A method ofpartially forming oxide layers as claimed in claim 3 or 4, wherein step(b) comprises heating said fixed portion of the oxide layer of step (a)together with said inorganic compound.